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  <title>Document</title>
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  <div></div>
  <script>
    const gift = '50g茶叶,清洗球'

    //1.可以把上面的字符串 转为数组['50g茶叶','清洗球']
    const arr = gift.split(',')
    console.log(arr)
    //2.根据数组的元素 ===> map遍历 ['<span>[赠品]50g茶叶</span>','<span>[赠品]清洗球</span>'
    const resArr = arr.map(el => `<span>[赠品]${el}</span>`)
    //3.讲得到数组转为字符串 放到div中显示
    document.querySelector('div').innerHTML = resArr.join('</br>')
  </script>
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